1. Field
Example embodiments provide an organic photoelectronic device and an image sensor.
2. Description of the Related Art
A photoelectronic device converts light into an electrical signal using photoelectronic effects, and may include a photodiode, a phototransistor, etc. The photoelectronic device may be applied to an image sensor, a solar cell, an organic light emitting diode, etc.
An image sensor including a photodiode requires relatively high resolution and thus a relatively small pixel. At present, a silicon photodiode is widely used. However, the silicon photodiode may have a problem of deteriorated sensitivity because the silicon photodiode has a relatively small absorption area due to relatively small pixels. Accordingly, an organic material that is capable of replacing silicon has been researched.
The organic material has a relatively high extinction coefficient and selectively absorbs light in a particular wavelength region depending on a molecular structure, and thus may simultaneously replace a photodiode and a color filter and resultantly improve sensitivity and contribute to relatively high integration.
However, the organic material may be different from silicon due to relatively high binding energy and a recombination behavior, and thus an organic photoelectronic device including the organic material may show relatively low efficiency compared with a silicon-based photoelectronic device.
This relatively low efficiency may be solved by applying a reverse bias voltage to the organic photoelectronic device, but the organic photoelectronic device may have relatively high dark current density due to carrier charges injected therein in the reverse bias state.
In addition, the organic material may be thermally weak and thus may be deteriorated in a subsequent process requiring a relatively high temperature. Therefore, the performance of the organic photoelectronic device may be deteriorated.